Rotary ironer for ironing essentially rectangular pieces of cloth

ABSTRACT

The invention relates to a rotary ironer comprising at least one essentially horizontally located ironing roller having a circular-cylindrical surface and being rotatably journalled about an axis of rotation through the centre of the roller, and wherein, for each ironing roller, there is provided an ironing pan, wherein the ironing pan is configured from two flexible, essentially rectangular steel plates that are mutually spaced apart, but being closely joined along their periphery, whereby they combine to form a hollow, flexible ironing pan that is able to adapt to the circular-cylindrical surface of the ironing roller and wherein, on the ironing pan at one or more positions along the axis of rotation of the ironing roller, is configured one or more supply pipes, integrally with the ironing pan, for supplying steam to the cavity of the ironing pan. The invention is characterised in that the integral supply pipes at each position on the ironing pan are configured as separate pipes, there being on the integral supply pipes at each position configured separate coupling flanges/stubs for connecting steam supply pipes to the integral supply pipes.

The present invention relates to rotary ironers for ironing inparticular substantially rectangular pieces of cloth, such as bed linenand tablecloths, and wherein the rotary ironer comprises at least oneessentially horizontally arranged and rotatably journalled ironingroller that has two ends, and wherein the ironing roller is providedwith an ironing pan that encloses a part of the circumference of theironing roller essentially throughout the entire length of the ironingroller, and wherein the ironing roller and the ironing pan thus form asupply side, whereby by means of the ironing roller the piece of clothis pulled into the abutment area between the ironing roller and theironing pan, and a discharge side opposite the supply side, wherein thepiece of cloth is yet again pushed out of the ironing roller.

Conventional rotary ironers of this kind very often comprise a veryrigid and inflexible ironing pan that is configured with very largematerial thicknesses. These rotary ironers are most often heated bymeans of condensing steam, the ironing pan being able to easily resistthe super-atmospheric pressure of the steam to be supplied to theironing pan in order to obtain the desired ironing temperature.

It is a problem of these prior art ironing pans that even very smallirregularities in the surface of the ironing pan that faces towards theironing roller during use will result in varying friction, which isundesirable in rotary ironers for the sake of ensuring as good andreliable ironing of the pieces of cloth as possible. The prior artinflexible ironing pans therefore involve quite a lot of machining ofthe rigid and inflexible ironing pan to ensure that it matches theironing roller well. However, it is an advantage of these rotary ironersthat, once the ironing pan as such is completely machined, it isdimensionally very stable and thus yields a high degree of freedom forconfiguring other component parts in the rotary ironer without therebyentailing diverse friction conditions.

Additionally it applies that the rigid pans expand in case of increasingpressure and temperature, which means that the contact pressure betweenroller and pan decreases to each side due to this expansion. The contactpressure being of considerable consequence to the drying capacity of therotary ironer, this means that—albeit the increasing temperaturegradient entails more thermal energy—the thermal and pressure expansionof the rigid pan involves a loss of capacity. The same phenomenon occurswhen the felt coating on the rotary ironer is worn, whereby the diameterof the roller is reduced.

In order to avoid the drawbacks of the above-mentioned technique,steam-heated ironing pans have been devised that are very flexible,thereby enabling them to elastically adapt to the outer shape of theironing roller.

Examples of such ironing pans are taught in eg EP patent No. 573,402, DEpatent application No. 19757756 and U.S. Pat. No. 3,118,240, wherein theironing pans are configured of two flexible, substantially rectangularsteel plates that are spaced apart, except that they are closely joinedalong their periphery and in a number of spot joints within theperiphery, whereby they combine to form a hollow flexible ironing pan,and wherein—on the ironing pan at each of the ends of the ironingroller—one ore more supply tubes is/are configured that are integralwith the ironing pan for supplying steam to the cavity of the ironingpan.

By the latter rotary ironers it is known to supply steam via a tubularsystem joined to the ironing pan by welding and extending longitudinallyof the ironing pan and the ironing roller from a coupling flange/stub atthe one end of the ironing roller. In order to counteract that thesetubular systems cause the flexible ironing pan to be deformed by thermalexpansion and contraction of the tubular members to contract, thesetubular systems are provided with one or more relief areas in the formof bends that increase the elasticity of the tubular system in thatthese bends allow the tubular system to be deformed in principle like aharmonica.

However, another problem that occurs in case of the latter flexibleironing pans that are heated by condensing steam is that the desiredtemperature on the surface of the ironing pan presupposes that steam issupplied under a certain pressure. This means that, in principle, theironing pan is considered to be a pressurized container, which meansthat safety precautions are to be made during construction of theironing pan.

Thus, it is the object of the present invention to provide a rotaryironer and an ironing pan, whereby the safety is increased—other thingsbeing equal, while simultaneously the loads, if any, of the tubularsystem on the ironing pan are further reduced.

In accordance with the invention this is obtained by the integral supplytubes being at each position on the ironing pan configured as separatetubular members in that, on the integral supply tubes, at each positionthere are configured separate coupling flanges/stubs for coupling ofsteam supply tubes onto the integral supply tubes.

The integral steam supply tubes being at each position longitudinally ofthe ironing roller and thus at each position on the ironing panseparated from each other rather than constituting a welded supply tubethat extends along the entire ironing pan, it is thus ensured that nopower influences are transmitted as a consequence of thermal expansionsand contractions via these tubes like to the ironing pan. Simultaneouslyit is obtained that the overall volume of the tubular system can bereduced considerably, in particular due to the prior art relief zoneswelded onto the ironing pan being redundant, thereby, other things beingequal, providing a higher degree of safety, the safety in connectionwith pressurized containers being often calculated as the overall volumeof the container multiplied by the pressure to which the container isexposed.

By a preferred embodiment there is exclusively configured integral steamsupply tubes in particular centrally on the ironing pan seen in relationto the axis of rotation of the ironing roller.

By an alternatively preferred embodiment such supply tubes areconfigured exclusively at each end of the ironing pan, and in thiscontext the overall container volume of the ironing pan isadvantageously further reduced by the coupling flanges/stubs beingconfigured at each their end of the ironing roller and hence the ironingpan.

By a further preferred embodiment the steel plate that, during use ofthe rotary ironer, faces towards the ironing roller is configured fromblack steel or ferritic steel, which, other things being equal, entailsthat a lower steam pressure can be applied than was necessary in theevent that stainless steel was used, as it is known in particular fromDE patent application No. 19757756 and EP patent No. 573402; black steelor ferritic steel usually having a conductivity that is up to four timesas high as stainless steel.

In this context, both the steel plates that form the ironing pan arefurther advantageously constituted of black steel or ferritic steel,whereby undesired deformations of the ironing pan due to differences inthe thermal expansion coefficient of the plates are thus avoided.

By a further preferred embodiment of the invention the steel plate thatfaces towards the rotary ironer during use is constituted of a platewith a material thickness of between 2 and 6 mm. And preferably between3 and 5 mm. And the steel plate that faces away from the rotary ironerduring use has a material thickness of between 0.75 and 2 mm, andpreferably between 1 and 1.5 mm. Thereby an extremely flexible ironingpan is obtained which is extremely easy to manufacture by use ofconventional welding process without an ensuing need for considerablefurther processing of the surfaces of the rotary ironer to ensure auniform friction and a uniform contact pressure between the ironing panand the pieces of cloth that are pulled through the rotary ironer by theabutment of the rotating ironing roller thereon.

Additionally, the ironing pan may further comprise one or more dischargepipes for collecting and discharging condensed steam from the ironingpan interior; by configuring such discharge pipes at the bottom of theironing pan in the normal use position thereof such discharge pipes willbe located on a bent and thus relatively rigid area of the ironing pan,which means that high demands are not made to reducing the effect bywhich the discharge pipes influence the ironing pan.

In a preferred embodiment, the integral supply pipes are in flowcommunication and attached to the ironing pan at each of the corners ofthe rectangular steel plates, whereby steam is supplied to the rotaryironer at the uppermost edges thereof, and at each of the ends of theironing pan seen relative to the normal use position. This ensures gooddistribution of heat on the surface of the ironing pan.

Furthermore, in this context, two of the integral supply pipes locatedat least at the one end of the ironing pan advantageously extend fromthe ironing pan and slangtingly there below, thereby entailing a furtherreduction of the impact exerted by the integral supply pipes on theironing pan.

A further reduction of the influence of the integral supply pipes on theironing pan is furthermore achieved provided the two integral supplypipes at the one end of the rotary ironer are provided with each theircoupling stub/flange for releasable coupling of steam supply pipes tothe integral supply pipes.

By a further preferred embodiment of the invention the integral supplypipes at the one end of the ironing pan are releasably coupled to one ormore steam supply pipes that extend longitudinally of the ironing panand towards the opposite end thereof. Hereby it is achieved that theironing pan can easily be coupled to an existing steam supply plant atthe one end of the rotary ironer.

A preferred embodiment of the invention will be described in detail inthe following with reference to the drawing, wherein:

FIG. 1 is a sketch showing a rotary ironer according to the presentinvention, seen in a front view;

FIG. 2 is a sketch in the form of a sectional view along the line A-Ashown in FIG. 1.

FIG. 3 is a sketch showing the ironing pan shown in FIGS. 1 and 2 withsupply pipes and discharge pipes welded thereto. The ironing pan isshown in unfolded state and seen from the outside.

FIG. 4 is a sketch showing the ironing pan according to FIG. 3, whereinthe welding spots are shown.

FIG. 5 is a sectional view through the ironing pan shown in FIG. 4.

Thus, FIG. 1 is a sketch showing an ironing pan seen in a front view,wherein the ironing pan comprises frame parts 1, wherein is configuredan ironing roller 2 that can be caused by a not shown motor, by means ofthe gear 18, to rotate about the axles 4. Underneath the ironing rolleran ironing pan 5 is provided in a conventional manner, on which supplypipes 6 are mounted at each end of the ironing pan 5. In accordance withthe invention, it will appear that the two shown supply pipes 6 are notconnected to each other; rather they are separate and each provided witheach their mounting flange 8 for mounting of further steam supply pipes7, only a few of which are shown.

Due to this above-mentioned separation of the shown supply pipes 6 inthe two opposed ends of the ironing pan 5 it is thus achieved thatimpacts, if any, that were previously used for supplying steam to theprior art rotary ironers are reduced to a minimum with ensuing reductionof the risk of the elastic ironing pan being undesirably deformed.

Now FIG. 2 shows a sectional view of the ironing roller 2 shown in FIG.1 with ironing pan 5, seen along the line A-A according to FIG. 1.

It will thus appear that the ironing roller 2 has a direction ofrevolution as illustrated by the arrow C around the centre D formed bythe axles 4 shown in FIG. 1, whereby the ironing roller 2 and theironing pan 5 form a feed slot 9 for the introduction of pieces of clothbetween the ironing roller 2 and the ironing pan 5, following which thepiece of cloth is transported between the ironing roller 2 and theironing pan towards the outlet opening 10.

Now FIG. 2 shows that the supply pipes 6 shown in FIG. 1 are providedboth at the inlet 9 and the outlet 10, such that pressurized steam issupplied to the ironing pan 5 via these supply pipes 6 that are yetagain, via the shown coupling flanges 8 or stubs, coupled to not shownsteam supply pipes.

As will appear from FIG. 2, the ironing pan 5 forms a yoke in which theironing roller 2 can rest, and in a commonly known manner the ironingpan is suspended between the inlet 9 and the outlet 10 that thus formsthe upper areas of the ironing pan in the normal use position thereof.Moreover FIG. 2 shows that in the ironing pan 5 a discharge pipe 11 isconfigured, as is shown in detail in FIG. 3. This discharge pipe 11 is,as shown, provided with a separate coupling flange or stub 12.

Thus, FIG. 3 shows the ironing pan 5 shown in FIGS. 1 and 2 in unfoldedand plane state for the sake of overview. Thus the ironing pan 5 is, aswill appear, constituted of two essentially rectangular plates, joinedby welding, as will appear in further detail from FIG. 4, but whereinthe plate has an inlet edge 9 a and an outlet edge 10 a and an edge 14at each end of the ironing pan plate 5. Furthermore, from FIG. 3 it willappear more clearly that the discharge pipe 11 is configured in a commonconventional manner with pipe bends 13 that are configured with a viewto reducing the forces by which the discharge pipe 11 influences theironing pan 5 and that may occur in case of diverse expansions andcontractions due to the heat expansion coefficients of the materials.

According to the invention the discharge pipe can be configured as twoseparate pipes with separate coupling flanges or stubs, as is providedin accordance with the invention in connection with the supply pipes 6.By the shown preferred embodiment, however, this alternative is not putto use due to the ironing pan being, in the area where the dischargepipe 11 is provided, configured to be relatively rigid due to the shapeof the ironing pan.

Now, FIG. 4 shows the ironing pan 5 shown in FIG. 3 in the same unfoldedstate, but without the supply pipes 6 and discharge pipes 11 shown inFIG. 3. In turn, it is shown herein that the two plates are joined toeach other by welding face to face in all the shown singular points 15and at the periphery of the plates, which is constituted by the two endedges 14 and the inlet edge 9 a and the outlet edge 10 a in combination.

Furthermore, FIG. 4 shows the supply apertures 16 that form the passagefor steam from the supply pipes 6 to the interior of the ironing pan 5and the corresponding discharge apertures 17 that form passage from theinterior of the ironing pan 5 to the discharge pipes 11.

Finally, FIG. 5 shows a detail of the ironing pan 5 shown in FIG. 4,shown in a sectional view. From here it will thus appear that the twoplates, joined by welding, have mutual contact merely via the twoabove-mentioned welded areas and, between these, they are configuredsuch that they create a flow path that allows steam to pass across theentire surface of the ironing pan from the supply openings 16 to thedischarge openings 17. This configuration can be performed as apre-shaping of the one of the plates, but is preferably performed byproviding a powerful hydraulic super-atmospheric pressure between theplates after they have been joined by welding.

1. A rotary ironer comprising at least one essentially horizontallylocated ironing roller that has a circular-cylindrical surface and isrotatably journalled about an axis of rotation through the centre of theroller, and wherein, for each ironing roller, there is provided anironing pan having two ends and between these two ends forming a yoke inthe form of a cylinder face that partially encloses a part of thecircumference of the ironing roller essentially in the full length ofthe ironing roller, and wherein the ironing roller and the ironing panthus form a supply side, where the piece of cloth will, due to therotation of the ironing roller, by means of the ironing roller be pulledinto the abutment area between the ironing roller and the ironing pan,and a discharge side, opposite the supply side, where the piece of clothis yet again pushed out of the ironing roller, and wherein the ironingpan is configured from two flexible, substantially rectangular steelplates that are mutually spaced apart, but being closely joined alongtheir periphery, whereby they combine to form a hollow, flexible ironingpan that is able to adapt to the circular-cylindrical surface of theironing roller and wherein, on the ironing pan, at one or more positionsalong the axis of rotation of the ironing roller, is configured one ormore supply pipes, integrally with the ironing pan, for supplying steamto the cavity of the ironing pan, characterised in that the integralsupply pipes at each position on the ironing pan are configured asseparate pipes, there being on the integral supply pipes at eachposition configured separate coupling flanges/stubs for connecting steamsupply pipes to the integral supply pipes.
 2. A rotary ironer accordingto claim 1, characterised in that integral steam supply pipes areconfigured exclusively essentially centrally on the ironing pan, seen inrelation to the axis of rotation of the ironing roller.
 3. A rotaryironer according to claim 1, characterised in that at least integralsteam supply pipes are configured at both ends of the ironing pan, seenin relation to the axis of rotation of the ironing roller.
 4. A rotaryironer according to claim 3, characterised in that the couplingflanges/stubs are configured at each end of the ironing pan.
 5. A rotaryironer according to claim 1 or 2, characterised in that the steel platefacing towards the ironing roller during use of the rotary ironer ismade of black steel or ferritic steel.
 6. A rotary ironer according toclaim 5, characterised in that both the steel plates that form theironing pan are made of black steel or ferritic steel.
 7. A rotaryironer according to claim 1, wherein the steel plate facing towards theironing roller during use has a material thickness of between 2 and 6mm, and in that the steel plate facing away from the ironing rollerduring use has a material thickness of between 0.75 to 2 mm.
 8. A rotaryironer according to claim 1, wherein the ironing pan further comprisesone or more discharge pipes for collecting and discharging condensedsteam from the ironing pan interior, said discharge pipe(s) beingconfigured at the area on the ironing pan which is located lowermost inthe normal in-use position of the ironing pan.
 9. A rotary ironeraccording to claim 1, wherein the integral supply pipes are in flowcommunication with and attached to the ironing pan at each of thecorners of the rectangular steel plates, whereby steam is supplied tothe ironing pan at the uppermost edges thereof.
 10. A rotary ironeraccording to claim 9, characterised in that, at least at the one end ofthe ironing pan, two of the integral supply pipes extend from theironing pan and slantingly there below.
 11. A rotary ironer according toclaim 10, characterised in that the two integral supply pipes at the oneend of the ironing pan are provided with each their coupling stub/flangefor releasable coupling steam supply pipes to the integral supply pipes.12. A rotary ironer according to claim 10 or 11, characterised in that,to the integral supply pipes at the one end of the ironing pan, one ormore steam supply pipes is/are releasably coupled that extendlongitudinally to the ironing pan and towards the opposite end of it.13. A rotary ironer according to claim 7, wherein the steel plate facingtowards the ironing roller during use has a material thickness ofbetween 3 and 5 mm, and in that the steel plate facing away from theironing roller during use has a material thickness of between 1 and 1.5mm.